Company tried to show parasites could fight Crohn’s disease

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Coronado Biosciences of Burlington saw its stock tumble 67 percent Monday after announcing the failure of its phase 2 clinical trial for a treatment of Crohn’s disease, an immune disease causing bowel inflammation.

The company had hoped to show that whipworms, a kind of parasite, could be used to distract the immune system of someone with Crohn’s, turning the immune system attack against the worms instead of the digestive tract.

The idea is based on the “hygiene hypothesis,” which argues that many of the diseases on the rise today are the result of over-cleaning of the parasites with which we co-evolved. Although parasites can be dangerous, it is possible that they also help tune our immune system, according to scientific research.

In a conference call this morning, Coronado chief executive Dr. Harlan F. Weisman said he was disappointed with the results. “This is certainly not a phone call I anticipated making,” he told analysts and investors. He declined to detail the results extensively, saying he and researchers had not yet had time to analyze them.

But he said the trial did not meet its stated primary goal of significantly improving a measure of Crohn’s disease severity, or a secondary goal of achieving remission. Patients with the most severe disease showed improvement, he said, but there were not enough of them to reach statistical significance. The patients with less severe cases did not fare any better on the whipworm eggs than they did on the placebo, he said.

It’s not clear why the trial failed. Weisman promised to release full results at a scientific meeting or in a publication in the near future. In the meantime, he said, he has not yet decided what the impact will be on the company, which had $100 million in assets as of Sept. 30.

“That’s something that will occupy management’s attention over the next few days to couple of weeks,” Weisman said.

Coronado’s share price fell on to $1.91 from $5.77 on Friday.

In the Coronado trial, half of 250 volunteers swallowed a drink containing 7,500 pig whipworm eggs every two weeks for 12 weeks, and half drank a placebo.

Previously, small studies had shown that the eggs, which mature into worms in the digestive tract and can survive a few months without passing into the bloodstream, could safely reduce symptoms of Crohn’s.

A second major trial of the worms is underway in Europe, run by Dr. Falk Pharma. Weisman said an interim report suggested patients were responding well in that trial, and a second interim report is due shortly.

So-called helminth therapy, using parasites to override immune diseases, has gained popularity in recent years after early studies showed effectiveness against a variety of diseases.

A registry of clinical trials run by the federal government shows two dozen trials underway with pig whipworms — half to treat diseases such as multiple sclerosis, autism, peanut and tree nut allergies, celiac disease, psoriasis, and ulcerative colitis; and the other half to treat people with whipworms, which can cause bloody diarrhea and are still endemic in many parts of the world, affecting 4.5 billion people.